Gantry robots of various types are known in fie prior art. Gantry robots generally comprise an apparatus mounted movably on at least one rail. Gantry robots often operate along three axes.
Types of gantry robots include open gantry robots and closed gantry robots. Open gantry robots are cantilevered. Closed gantry robots are supported between two generally symmetrical support members.
Linear bearings are often used to support and to provide the motion of gantry robots. A linear bearing generally comprises a block, a rail, and bearings contained in races. The block, bearings, and races travel along the rail.
Linear bearings are very rigid and precise. As a result, it is desirable to keep very clean the bearings. Air borne contamination, such as talc, carbon black, dirt, and graphite powder can damage linear bearings. Because the bearings are exposed to the rail, which is often coated with grease from contact with the lubricated bearings, any contamination of the rail will ultimately contaminate the bearings.
Also because linear bearings are very rigid and precise it is desirable to minimize stress due to mounting errors. For example, the surfaces upon which blocks and nails are placed may contain numerous variations. Similarly, the rails may not be completely straight or parallel. Such mounting errors stress the rigid and precise bearings as they travel along the rail and cause the bearings, over time, to fail.